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Cell division is the process by which cells replicate in order to replace cell loss, repair tissue damage and reproduce the organism. Two types of cell division are encountered in the Eukaryotic cell viz. Mitotic and Meiotic divisions.
In multicellular organisms, cell reproduction is required to form propagules and gametes. A number of factors are known to induce cell division. The important ones are as follows: Minimum growth: A newly formed cell does not divide immediately.
Before dividing the cell must not only duplicate, but also assemble DNA into a manageable form. At the beginning of cell division DNA is coiled into rather short and thick “trunks” visible under light microscope. It is this form of DNA which was originally identified as chromosomes. WHAT SHOLD THE CELL DO NEXT? • Dissolve nuclear membrane.
1 Μαΐ 2003 · In creating the mitotic spindle and the contractile ring, natural selection has engineered fascinating precision machines whose movements depend upon forces generated by ensembles of cytoskeletal...
Meiosis is a specialized type of cell division sharing many features with mitosis. The main difference is that meiosis involves two successive nuclear divisions that produces four haploid cells. Each gamete, or sex cell, contains half the number of chromosomes. In humans, each gamete contains 23 chromosomes. Fertilization of an egg by a sperm, each
In eukaryotes, cell division occurs in two major stages. The first stage, division of the cell nucleus, is called mitosis. The second stage, division of the cell cytoplasm, is called cytokinesis. Genetic information is passed from one generation to the next on chromosomes. Before cell division, each chromosome is duplicated, or copied.
I. Cell division -- introduction - roles for cell division: • reproduction -- unicellular organisms (mitosis) • growth and tissue repair in multicellular organisms (mitosis) • production of gametes, sex cells, for sexual reproduction (meiosis) - for an eukaryotic cell to divide a few events required: • reproductive signal -- signal from ...
